I was just scrubbing over some WTC7 collapse video when I noticed something new to me. When the East penthouse falls though the building it creates a visible wave on the windows, presumable as they are twisted or pushed out somehow by the changes in pressure. The scale of the pressure is also visible by the smoke being sucked in at the top of the building.

This is relevant because it appears to show the East Penthouse falling rapidly though the building, which is consistent with a collapse of C79/80/81 at a low level, well before the other columns failed.

I think some people, like @Tony Szamboti, have suggested that the East Penthouse actually only fell in a few floors, and that lower interior column failures were simultaneous, but this seems at odds with that.

You can kind of see this in the more familiar footage on the right, but the angle and lighting are not perfect, and there's more obscures.

When the East penthouse falls though the building it creates a visible wave on the windows

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ha! honestly, I also saw this a few weeks ago in a WTC7-thread here when someone posted the dan-rather(?)-video from cbs (the same as in your video) and thought making a video about, but was under the impression it would be already known. and pure lazyness of course. well, that will teach me

One fascinating quality of this footage (and the CBS Building Cam) is the changing reflection in the windows that reveals Penthouse Free Fall within the building (or at least a speed too close to free fall acceleration).

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The "Penthouse free fall" link is a broken youtube. It's also linked from:

If my memory is correct femr2 and associates on The911Forum did a fair amount of analysis of "waves" of varying reflectivity and therefore the probable causes. Certainly femr2 set the standard as "go to guy" on motion analysis from videos. May not be the easiest material to locate - I haven't looked.

(And anyone searching that forum be aware that its mission was and is "...to bring together sincere researchers, irrespective of creed, for constructive dialog and collaboration on 9/11 issues." So in today's language it was and is "truther friendly" in contrast with the then JREF forum from which it was a "break-away")

What others here may not tell you is that while the vertical kink in the east penthouse does point to a failure of column 79 it only tells you it failed below the penthouse, not where that failure occurred. Interestingly, the evidence shows the east penthouse only came down into the main building a couple of stories which would indicate that column 79 only failed high in the building. The points of evidence for this are

1. Daylight can only be observed through the windows of the top story.
2. The shock wave goes top to bottom.
3. Window breakage only occurs from the roofline down 15 stories.
4. There is no exterior column deformation observed on the east side as there would be if lateral support was lost.
5. There is no dust emanating from windows on the east side until the exterior starts coming down and the east penthouse dropped into the building 6 to 7 seconds before that.

What this also means is that all 24 core columns were still intact for most of their height after the east penthouse fell. To cause a simultaneous drop of all four walls of the building, as observed, all 24 core columns would have to be pulled nearly simultaneously starting in the center a fraction of a second earlier.

A reason the east penthouse might have been taken down separately first is that it was eccentrically located in the northeast corner. The screen wall and west penthouse, which also sat on the roof, were located in the center of the 144 foot wide building.

Of course, this situation is a lot more plausible and would explain the observations much better than the Rube Goldberg situation that NIST and some others are trying to feed us. Several years after the release of the NIST WTC 7 report, when the drawings were released, it was found that NIST needed to deceptively ignore, omit, and distort several pertinent structural features to even make it have any plausibility. Their analysis looks and sounds like a classic cover-up, where things don't naturally add up and the situation is then contrived.

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I responded to each point in the next post, and he didn't have a substantive response after that. As I noted, it is clear that the totality of the visible window breakage on the northern face of the building is inconsistent with Tony's theory that the collapse of the penthouse was a discrete, pre-collapse event. Mick's focus on the actual progression of the window breakage/distortion here makes that even clearer.

Tony's bizarre and indefensible theory re the penthouse collapse isn't so bizarre (though it is indefensible) when you realize he is simply trying to rationalize his continued belief in the occurrence of a controlled demolition of the building despite the fact that he has realized (and even admitted in his own words) that the so-called free fall period of the descent of the northern face of the building could occur as a result of a buckling of the exterior columns of the building if the interior columns had already collapsed. Of course, if he recognized the penthouse collapse for what it was (the beginning of the collapse of the interior columns), he would then be forced to recognize, based on his own stated understanding of the ability of the the so-called free fall period of the northern face to occur absent the interior columns, that the so-called free fall period of the northern face is not evidence of a controlled demolition, which runs counter to everything he and AE911Truth have argued for a decade or so. And so he is forced to rationalize an absurd, just-so theory about how the penthouse collapse can't possibly be the collapse of the inner columns.

Truthers, if you aren't convinced by Tony's flimsy arguments for the notion that the collapse of the penthouse was some sort of discrete, pre-collapse event, then congratulations! Thanks to Tony's helpful observation that the free fall period could occur via a buckling of the exterior columns, you can now understand that the observed collapse of WTC7 was entirely consistent with a progressive collapse as a result of fire. Welcome back to reality.

If my memory is correct femr2 and associates on The911Forum did a fair amount of analysis of "waves" of varying reflectivity and therefore the probable causes. Certainly femr2 set the standard as "go to guy" on motion analysis from videos. May not be the easiest material to locate - I haven't looked.

No doubt recent discussion *over there* has been seen by folk here, so probably prudent to summarise...

Folk didn't like the word *shockwave*, preferring *flexure*, which is fine.

As far as I'm concerned the behaviour being highlighted would tend to support the notion of failure low-down in WTC 7 beneath the East penthouse propogating rapidly up inside the building, until it reached the East penthouse, at which the *flexure* caused by penthouse structure itself can be seen traversing down inside the building.

The start of East penthouse descent is in very close proximity to the upward *flexure*, and would tend to suggest quite a complex internal behaviour (you could almost say the start of the East penthouse descent began before the upwards flexure, which would make describing the internal behaviour a bit difficult)

By "over there" femr2 will be referring to JREF where for several years he steadfastly maintained his own integrity and support of his work against the prevailing climate. I think you are probably aware of the JREF "climate" and personality conflict issues that led to the establishment of The911Forum.

femr2 was careful to use the phrase low down in the building... because the bottom is eclipsed by buildings in the foreground. But his analysis seemed to strongly support the notion that the collapse of the EPH traveled down thru the visible height of the north facade... and was not a local event up top as Tony claims.

If columns 79, 80 and 81 failed near the bottom as NIST posits, then there would be no shock wave as every floor would be falling at the same time.

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It’s not really a shockwave. It’s just visible deformation. And it is happening all along the face at once from the outset, not just in a top down manner, even though the final downward ripple of deformation is relatively pronounced.

It’s not really a shockwave. It’s just visible deformation. And it is happening all along the face at once from the outset, not just in a top down manner, even though the final downward ripple of deformation is relatively pronounced.

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I was referring to the collapse of the EPH, not the whole building.

A failure of the columns under the EPH near the bottom of the building would not create a shock wave or deformation from the top down as we can see in the video because all the floors from the top to the bottom would be falling from simultaneously. Therefore, the deformation would also be on every floor simultaneously.

The top down shock wave or deformation is what would happen if the EPH and the machinery it contained were to
impact the 47th floor.

Why? That makes no sense. Why would the penthouse stop after ten floors? What is in this wave, and why does it proceed down the face of a building in a blob?

It looks more like the penthouse just fell through all the visible floors, accelerating as it goes. (why would a wave accelerate?)

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The EPH stopped falling at the 47th floor (one floor, not ten) as is evidenced by light coming thru a few windows on the 47th floor but none of the floors below that. Had the EPH and its contents fallen further, there would have been light coming thru windows on those floors too. The wave is therefore a shock wave. The wave does not accelerate that I can see. That would take a frame by frame analysis to say for sure.

A failure of the columns under the EPH near the bottom of the building would not create a shock wave or deformation from the top down as we can see in the video because all the floors from the top to the bottom would be falling from simultaneously. Therefore, the deformation would also be on every floor simultaneously.

The top down shock wave or deformation is what would happen if the EPH and the machinery it contained were to
impact the 47th floor.

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Why does visible deformation occur at the bottom of the visible portion of the north face simultaneously with the penthouse falling through the roof line? This deformation precedes the arrival of the top-down "ripple" of deformation that subsequently moves down across the north face of the building. You can see it if you watch the full length collapse in real time that Mick previously posted above. This deformation is wildly inconsistent with a theory that the penthouse collapse event was localized to only the top floors of the building.

And can you articulate with more specificity why you think the downward ripple of deformation that appears to roughly follow the passage of the penthouse through the roof line is impossible in NIST's scenario? What exactly is causing that deformation in your theory? If you note that the whole face was undergoing a complex series of deformations from the outset of the penthouse collapse as I showed you above, its continued deformation in an increasingly pronounced way doesn't strike me as strange or inexplicable; in fact, it looks largely consistent with the NIST computer simulation of how debris moved through the building in a chaotic way after column 79 buckled. In the animation NIST provided, the penthouse debris does not simply fall cleanly to the ground; it hits various remaining portions of the structure on the way down, causing further damage.

The EPH stopped falling at the 47th floor (one floor, not ten) as is evidenced by light coming thru a few windows on the 47th floor but none of the floors below that. Had the EPH and its contents fallen further, there would have been light coming thru windows on those floors too. The wave is therefore a shock wave. The wave does not accelerate that I can see. That would take a frame by frame analysis to say for sure.

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Re the light coming through the windows, can you, in reference to a certain camera angle, specify exactly where and when you'd expect to see more light if NIST's scenario were broadly true?

The EPH stopped falling at the 47th floor (one floor, not ten) as is evidenced by light coming thru a few windows on the 47th floor but none of the floors below that. Had the EPH and its contents fallen further, there would have been light coming thru windows on those floors too.

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You can only see the light in a few of the upper windows because you can look up through the hole to see the sky.

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Re the light coming through the windows, can you, in reference to a certain camera angle, specify exactly where and when you'd expect to see more light if NIST's scenario were broadly true?

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Exactly. I have not yet seen an actual analysis of this, just a bare claim that blue sky should be visible through more than just the windows of the two top floors. That analysis would have to recreate the geometry of the relevamt lines of sight - distance of camera to foot of window, distance from the third-highest floor to the roof line, depth of the building, etc.

The EPH stopped falling at the 47th floor (one floor, not ten) as is evidenced ....

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What would stop it once it got moving?

Sure - enjoy debating the details such as light paths through windows BUT dont miss the issues of dubious base premises.

What Christopher 7 is proposing is repeating the same errors of T Szamboti's "Missing Jolt" twisted a bit and translated to the WTC7 scenario. "Missing Jolt" wrongly assumed a false start premise and went looking for a jolt that never could have occurred. The Twin Towers Top Blocks started moving and there was nothing to stop them. The actual mechanism understood by some and still misunderstood by many BUT the TB did not stop because the mechanism of the collapse had no way of stopping it.

At WTC 7 the EPH started falling. What could stop it? Can anyone explain how it could stop? Without repeating the errors which were repeated ad nauseam in discussion of MJ?

Exactly. I have not yet seen an actual analysis of this, just a bare claim that blue sky should be visible through more than just the windows of the two top floors. That analysis would have to recreate the geometry of the relevamt lines of sight - distance of camera to foot of window, distance from the third-highest floor to the roof line, depth of the building, etc.

This has not been done, afaik.

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I took a bash at it:

Roughly the line of sight does not really go through the roof, it almost entirely goes through the east wall. Apparent if we view it in X-ray mode:

(Note this is an approximate positioning of the other buildings, as the ones I downloaded seemed to be slightly off in size, however I think it's very close for line-of-sight through the windows).

Why does visible deformation occur at the bottom of the visible portion of the north face simultaneously with the penthouse falling through the roof line? … This deformation is wildly inconsistent with a theory that the penthouse collapse event was localized to only the top floors of the building.

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A couple windows on the 40th floor (not at the bottom of the visible part of the building) go dark before the shock wave gets there. I have no explanation for that. However, if the columns failed at the lower floors then there would be windows going dark all up and down the face.

And can you articulate with more specificity why you think the downward ripple of deformation that appears to roughly follow the passage of the penthouse through the roof line is impossible in NIST's scenario?

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Not impossible. However, if the interior columns failed near the bottom of the building, there would be simultaneous distortions from bottom to top as every floor would be pulling inward on the exterior wall (unevenly). A ripple starting at the top was cause by an event up there.

I was just scrubbing over some WTC7 collapse video when I noticed something new to me. When the East penthouse falls though the building it creates a visible wave on the windows, presumable as they are twisted or pushed out somehow by the changes in pressure. The scale of the pressure is also visible by the smoke being sucked in at the top of the building.

This is relevant because it appears to show the East Penthouse falling rapidly though the building, which is consistent with a collapse of C79/80/81 at a low level, well before the other columns failed.

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Have you measured what speed the wave is moving at?

Any idea what the cause of the wave might be? Looking at the NIST model, nothing jumps out that seems to account for it. At the start of their model, the column under the penthouse simply buckles, and all floors attached to it descend at the same time.

Does a similar wave appear before the collapse of the remainder of the building?

Any idea what the cause of the wave might be? Looking at the NIST model, nothing jumps out that seems to account for it.

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Doesn't this falling red area of similar size to the falling "wave" kind of jump out?

It's the penthouse, of course. but perhaps more importantly it's the top of the interior collapse, which you might view a a kind of top heavy piston. I suspect the cause of the wave is just air pressure moving the windows outwards changing their reflection angle a bit.

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“Why does visible deformation occur at the bottom of the visible portion of the north face simultaneously with the penthouse falling through the roof line? … This deformation is wildly inconsistent with a theory that the penthouse collapse event was localized to only the top floors of the building.”

A couple windows on the 40th floor (not at the bottom of the visible part of the building) go dark before the shock wave gets there. I have no explanation for that. However, if the columns failed at the lower floors then there would be windows going dark all up and down the face.

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I think you should watch the video more carefully at around the 4 second mark (maybe try rapidly pausing and unpausing). Between 4 and 7 seconds, there are significant visible distortions on the bottom left side of the visible face of the building. These distortions are most apparent in both the middle and left angles. Perhaps some one who is more technically savvy than I can isolate and slowdown the time frame in question, but I think the distortion I'm describing is readily apparent in the video even at its regular speed. The bottom line is that something was happening in the building along the entirety of the visible portion eastern side of its north face from the very outset of the visible collapse of the penthouse.

“And can you articulate with more specificity why you think the downward ripple of deformation that appears to roughly follow the passage of the penthouse through the roof line is impossible in NIST's scenario?”

Not impossible. However, if the interior columns failed near the bottom of the building, there would be simultaneous distortions from bottom to top as every floor would be pulling inward on the exterior wall (unevenly). A ripple starting at the top was cause by an event up there.

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It looks to me like there were simultaneous distortions throughout the face, though they were not necessarily as pronounced as the distortions in the final ripple. I'm not sure what conclusion should be drawn from that. I think Mick's theory that the final top-down ripple was largely caused by air displaced by the debris seem plausible, and the demonstration he made in the post directly above lends some additional credence to the ripple being related to the top of the falling debris wave (and the NIST report having the motion of that debris generally correct). It also seems plausible that some portions of the distortion were caused by other aspects of the internal collapse (falling debris coming into contact with the face or un-collapsed elements still connected thereto, the moment frame redistributing loads rapidly, etc.).

It is possible to see light thru the windows even when there is not a direct line of sight to the sky the same as we can see the building even thought there is no sunlight hitting it.

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I don't think this is really responsive to my request or really a helpful to get us to a framework from which we can analyze whether the visible light in the extant video is consistent or inconsistent with NIST's theory. Can you please choose a video frame of reference as Mick has done and provide a more detailed explanation of your point in reference thereto?

If columns 79, 80 and 81 failed near the bottom as NIST posits, then there would be no shock wave as every floor would be falling at the same time.

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Each floor section was supported axially by columns... but they slabs were connected laterally to adjacent and initially unaffected columns. there for there was resistance at each floor level... Or.... maybe the mass at the top just smashed thru one floor at a time when it lost partial axial support.

I notice that small & partial window wave is just seen descending before the roof of the penthouse machine room roof and walls begin to fall down & inwards.. I'd suspect heavy plant equipment is on its way down though the fire & impact weakened floors adding & creating structure failure and initiating the full penthouse collapse.

I think you should watch the video more carefully at around the 4 second mark (maybe try rapidly pausing and unpausing). Between 4 and 7 seconds, there are significant visible distortions on the bottom left side of the visible face of the building. These distortions are most apparent in both the middle and left angles. Perhaps some one who is more technically savvy than I can isolate and slowdown the time frame in question, but I think the distortion I'm describing is readily apparent in the video even at its regular speed. The bottom line is that something was happening in the building along the entirety of the visible portion eastern side of its north face from the very outset of the visible collapse of the penthouse.

It looks to me like there were simultaneous distortions throughout the face, though they were not necessarily as pronounced as the distortions in the final ripple. I'm not sure what conclusion should be drawn from that. I think Mick's theory that the final top-down ripple was largely caused by air displaced by the debris seem plausible, and the demonstration he made in the post directly above lends some additional credence to the ripple being related to the top of the falling debris wave (and the NIST report having the motion of that debris generally correct). It also seems plausible that some portions of the distortion were caused by other aspects of the internal collapse (falling debris coming into contact with the face or un-collapsed elements still connected thereto, the moment frame redistributing loads rapidly, etc.).

Ok, great.

I don't think this is really responsive to my request or really a helpful to get us to a framework from which we can analyze whether the visible light in the extant video is consistent or inconsistent with NIST's theory. Can you please choose a video frame of reference as Mick has done and provide a more detailed explanation of your point in reference thereto?

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There is no other video that I know of that shows the light coming thru the windows on the 47th floor. However, I occurred to me that if the EPH and its contents fell past the 47th floor we would be seeing light thru all the windows on that floor. The reason we don't is because there's a pile of debris blocking the light.

There is no other video that I know of that shows the light coming thru the windows on the 47th floor. However, I occurred to me that if the EPH and its contents fell past the 47th floor we would be seeing light thru all the windows on that floor. The reason we don't is because there's a pile of debris blocking the light.

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The sunlight is coming from the southwest and the western mechanical penthouse is still standing at the moment in question. Looks to me like that's why you don't see a few windows completely brighten on the east side of the north face on the 47th floor, though it looks to me like there is a visible brightening of all such windows. Just rewatch Mick's loop and you can see the relationship between the western mechanical penthouse and the shadow across such windows pretty clearly as the western penthouse itself succumbs to the progressive collapse just moments before the northern face begins the rapid phase of its descent:

Doesn't this falling red area of similar size to the falling "wave" kind of jump out?

It's the penthouse, of course. but perhaps more importantly it's the top of the interior collapse, which you might view a a kind of top heavy piston. I suspect the cause of the wave is just air pressure moving the windows outwards changing their reflection angle a bit.

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It's not plausible that a falling section of penthouse would cause window deflections, while 30+ falling floor assemblies would not.

The sunlight is coming from the southwest and the western mechanical penthouse is still standing at the moment in question. Looks to me like that's why you don't see a few windows completely brighten on the east side of the north face on the 47th floor, though it looks to me like there is a visible brightening of all such windows. Just rewatch Mick's loop and you can see the relationship between the western mechanical penthouse and the shadow across such windows pretty clearly as the western penthouse itself succumbs to the progressive collapse just moments before the northern face begins the rapid phase of its descent:

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You are right about the screenwall shading the east end up to column 44. I did the research and the calculations. However, I contend that we would see defuse light thru windows at least a few stories down if the east end had hollowed out but I guess we will just have to agree to disagree on that point. Furthermore, I don't see the "visible brightening of all such windows" that you see.

I would also argue that the 4 windows to the right of the 2 that show sunlight have debris piled in front of them but not enough to block them completely.

In any case, this has been an interesting and informative discussion. Thank you.

At this point column 79 has descended about 20', pulling the girder between 79 and 44 and all the floors downward. There should be deflections in the north wall all along column 44 as it is pulled inward. The exterior walls have little strength in the horizontal plane perpendicular to them.